Studies on the topical treatment of experimental cutaneous leishmaniasis: the therapeutic effect of methyl benzethonium chloride and the aminoglycosides, gentamicin and paromomycin

BALB/c mice infected with either Leishmania major or Leishmania mexicana were treated twice a day for 10 days with an ointment containing 15% gentamicin or paromomycin, with or without 12% methylbenzethonium chloride (MBCl). It was found that topical application of either paromomycin or MBCl cured the parasite lesion, and that combined treatment with the two compounds had an additive effect. However, after four days' therapy there was a severe inflammatory response at the treatment site, and in most experiments mice relapsed and renewed lesion growth was observed. It is suggested that a non-specific inflammatory reaction may be an important component of the therapeutic response. In further experiments, L. major infected mice treated with paromomycin and MBCl which had cured but not relapsed 58 days after treatment were challenged with a similar dose of the homologous parasite. Lesions developed 16 days post-infection, and the number of parasites recovered from these lesions was similar to that recovered from lesions in control mice. Therefore no protective immunity had been induced by chemotherapy.     

Variants with reduced virulence derived from Leishmania major after mutagen treatment

After several in vitro treatments of a virulent population of Leishmania major with the mutagen, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), five clones (vir-) were obtained that did not produce cutaneous lesions after subcutaneous injection of 10(6) promastigotes. All the control clones (vir+) obtained from the non-mutagenized parasite population produced progressive cutaneous lesions with as few as 10(3) parasites. Late lesions were observed occasionally after injection of 10(7) vir- parasites. These late lesions appeared to result from the selection of virulent revertants, since parasites isolated from these lesions produced progressive lesions in BALB/c mice almost as readily as the control parasites. Two vir- clones, one vir+ clone and one revertant clone were examined for survival in BALB/c macrophages in vitro. All clones were taken up by the macrophages and transformed into amastigotes. However, vir- clones failed to multiply inside the macrophages. A vir- clone was found to protect mice against a subsequent challenge with vir+ parasites.     

Efficacy of paromomycin ointment in the treatment of cutaneous leishmaniasis: results of a double-blind, randomized trial in Isfahan, Iran

Although pentavalent antimonials are often used in the first-line treatment of cutaneous leishmaniasis (CL), they have several adverse effects. Intralesional administration of antimonials and other antileishmanial drugs can be painful. In the present, double-blind, randomized study, to determine if topical treatment with paromomycin is effective in the treatment of CL, 35 cases of CL were treated, twice daily for 30 days, with a commercial skin-care lotion containing 10% urea (the placebo) and another 30 were similarly treated with the same lotion to which paromomycin sulphate had been added (to give a concentration of 15%). Each case was assessed clinically 7, 14, 21 and 30 days after treatment began, and parasitologically 30 and 60 days after the initiation of treatment. Five (17%) and five (17%) of the cases treated with paromomycin showed complete healing, with the apparent clearance of amastigotes from their lesions, 30 and 60 days after treatment began, respectively. At the same time-points, however, the lesions on six (17%) and seven (20%) of the cases in the placebo group, respectively, also appeared to have healed completely. Ointment containing 15% paromomycin therefore appears ineffective in the treatment of CL, at least when applied twice daily for 30 days to the lesions of cases from an endemic area of Isfahan, Iran.     

Combined interleukin-12 and topical chemotherapy for established Leishmaniasis drastically reduces tissue parasitism and relapses in susceptible mice

The efficacy of the association of paromomycin sulfate (PA) with recombinant (r) interleukin (IL)-12 was investigated by topical treatment of BALB/c mice infected with Leishmania major that displayed fully developed cutaneous lesions. Although healing was observed in PA-treated groups, lesions recurred in 100% of these animals 70 days after treatment. In contrast, lesions were absent in a high proportion of PA- and rIL-12-treated mice 120 days after treatment. The PA/rIL-12-treated mice had a switch in cytokine response, from high IL-4 and low interferon (IFN)-gamma levels to low IL-4 and high IFN-gamma levels, and reductions in parasite load, dissemination of parasites, and inflammation. Thus, the association of rIL-12 to topical chemotherapy for leishmaniasis may be an important strategy for increasing cure rates and decreasing the incidence of relapse.     

Effects of long-term in vitro cultivation on the virulence of cloned lines of Leishmania major promastigotes.

The virulences of several clones from a single Leishmania major strain were studied in BALB/c mice. Clones showed the same pattern of infectivity and virulence two months after cloning as the parental population. After prolonged in vitro culture, however, it was apparent that two types of virulent clones existed: although the level of virulence remained stable in some clones, in others, such as C-11, it progressively decreased, as in the parental population. The progressive loss in virulence in a continuously cultured mixed population was probably due to selection, as the initial mixture of a stable virulent clone and a stable avirulent clone eventually yielded a totally avirulent promastigote population. After cultivation for 12 months, neither clone C-11 nor the parental population produced lesions in inoculated mice but virulent parasites were recovered from the inguinal nodes of the mice, possibly as a result of selection in vivo for virulent parasites.     

Randomized,Double-Blinded,Phase 2 Trial of WR 279,396 (Paromomycin and Gentamicin) for Cutaneous Leishmaniasis in Panama

In this randomized, double-blinded Phase 2 trial, 30 patients with Leishmania panamensis cutaneous leishmaniasis were randomly allocated (1:1) to receive once daily topical treatment with WR 279,396 (15% paromomycin + 0.5% gentamicin) or Paromomycin Alone (15% paromomycin) for 20 days. The index lesion cure rate after 6 months follow-up was 13 of 15 (87%) for WR 279,396 and 9 of 15 (60%) for Paromomycin Alone (P = 0.099). When all treated lesions were included, the final cure rate for WR 279,398-treated patients was again 87%, but the final cure rate for Paromomycin Alone-treated patients was 8 of 15 (53.3%; P = 0.046). Both creams were well tolerated with mild application site reactions being the most frequent adverse event. The increased final cure rate in the WR 279,396 group in this small Phase 2 study suggests that the combination product may provide greater clinical benefit than paromomycin monotherapy against L. panamensis cutaneous leishmaniasis.     

Colloidal, in vitro and in vivo anti-leishmanial properties of transfersomes containing paromomycin sulfate in susceptible BALB/c mice

The aim of this study was to develop transfersomal formulation with respect to dermal delivery of paromomycin sulfate (PM) for possible topical therapy of cutaneous leishmaniasis (CL). PM transfersomal formulations (PMTFs) with different percent of soy phosphatidylcholine, sodium cholate (Na-Ch) and ethanol were prepared and characterized for the size, zeta potential and encapsulation efficiency. The results showed that the most stable formulations with suitable colloidal properties were obtained by 2% Na-Ch which had average size of around 200nm. The in vitro permeation study using Franz diffusion cells fitted with mouse skin at 37°C for 24h showed that almost 23% of the PMTFs applied penetrated the mouse skin, and the amount retained in the skin was about 67% for both formulations; however, the percent of penetration and retention for PM conventional cream was 49 and 13, respectively. The 50% effective doses of PMTFs against Leishmania major promastigotes and amastigotes in culture were significantly less than cream and/or solution of PM. Selected PMTFs and empty transfersomes showed no cytotoxicity in J774 A.1 mouse macrophage cell line. Selected PMTFs was used topically twice a day for 4 weeks to treat L. major lesions on BALB/c mice, and the results showed a significantly (P<0.05) smaller lesion size in the mice in the treated groups than in the mice in the control groups, which received either empty transfersomes or phosphate-buffered saline (PBS) and also PM cream. The spleen parasite burden was significantly (P<0.01) lower in mice treated with selected PMTFs than in mice treated with PBS or control transfersomes, and PM cream. The results of this study showed that PMTFs prepared with 2% of Na-Ch with and without 5% ethanol might be useful as a candidate for the topical treatment of CL.     

Comparison of the effectiveness of two topical paromomycin treatments versus meglumine antimoniate for New World cutaneous leishmaniasis

The randomized, controlled study compared the therapeutic efficacy and safety of two paromomycin-containing topical preparations with the gold treatment standard, meglumine antimoniate, and with each other in 120 Ecuadorian patients with ulcerated lesions. The two paromomycin treatment comparisons were double-blinded. Group 1 (n = 14) received 15% paromomycin plus 12% methylbenzonium chloride (PR-MBCL) dissolved in a soft white paraffin base, applied twice daily for 30 days. Group 2 (n = 40) was also treated for 30 days with 15% paromomycin plus 10% urea (PR-U) dissolved in the same paraffin base. Group 3 (n = 40) received 20mg/kg/day of IM meglumine antimoniate (MA) for 10 days as per Ecuadorian Ministry of Public Health recommendations at the time of the study. The 10-day treatment was completed by 90% of the MA group compared to 72.5% of the PR-MBCL (X2 = 4.0, P = 0.045) and 75% of the PM-U (X2 = 3.1, P > 0.05) groups whose treatment regime lasted 20 days longer than the MA treatment. Post-treatment lesion burning, redness, inflammation, and soreness were more common in the two paromomycin groups compared to MA group (P < 0.05). The frequency of treatment-related side effects in the two paromomycin groups was similar. Six weeks after the start of treatment, 80.6% of MA subjects were clinically cured compared to 48.3% in the PR-MBCL (X2 = 6.1, P = 0.014) and 40% in the PM-U groups (X2 = 12.6, P = 0.002). By 12 weeks, the proportion of clinically cured subjects in the MA (91.7%) compared to PM-MBCL (79.3%) or PM-U (70%) groups was not significantly different (P > 0.05). MA-treated subjects clinically cured by 12 weeks had a faster mean healing time (29.5 +/- 12.2 days) compared to those in the PM-MBCL (versus 43.1 +/- 14.4 days, t = -3.7, P = 0.001) or PR-U groups (43.5 +/- 17 days; t = -3.2, P = 0.002). During the 48-week post-treatment follow-up period, infection reactivation was observed in 15.2% of the MA subjects compared to 17.4% in the PM-MBCL and 10.5% PM-U of subjects diagnosed as clinically healed by 12 weeks (P > 0.05). The results suggest that although the time required for the clinical healing of ulcerated lesions takes longer, topical paromomycin may be an acceptable therapeutic alternative in endemic areas where meglumine antimoniate is not available, is too costly or medically contraindicated.     

Humoral response of Meriones libycus to experimental infection with Leishmania major

The humoral responses of laboratory-reared jirds (Meriones libycus) to inoculation with various doses of Leishmania major were determined. The animals were inoculated intradermally with 10(2), 10(3), 10(5) or 10(7) promastigotes of a strain of L. major originally isolated from a Jordanian patient. The jirds were then bled at various intervals throughout the 26 weeks of the study, and the sera checked, by IFAT, for antibodies to homologous parasites. There were no detectable humoral responses in the animals inoculated with 10(2) promastigotes each or in parasite-free controls but a positive response was apparent in each of the other jirds. The animals given 10(3) promastigotes each required 3 months to become IFAT-positive whereas those given 10(5) and 10(7) parasites only needed 4 and 2 weeks, respectively. More than 50% of the animals inoculated with 10(3) parasites each developed strongly positive sera 2 months post-infection, whereas > 50% of the animals inoculated with 10(5) or 10(7) parasites each had strongly or very strongly positive sera 4 and 2 weeks post-inoculation, respectively. The data indicate that, in M. libycus inoculated with L. major, the time required for the humoral response to develop and its intensity are both dose-related.     

Randomized, controlled, double-blind trial of topical treatment of cutaneous leishmaniasis with paromomycin plus methylbenzethonium chloride ointment in Guatemala.

A double-blind, randomized trial was undertaken in Guatemala to determine the therapeutic efficacy of an ointment for the treatment of cutaneous leishmaniasis that contained 15% paromomycin and 12% methylbenzethonium chloride and that was applied twice a day for 20 days. The treatment group included 35 patients, and the placebo group included 33 patients. The initial clinical response rate (13 weeks after completing the treatment) was 91.4% in the treatment group and 39.4% in the placebo group. The final clinical response rate at the 12-month follow-up examination was 85.7% (31 of 35) in the treatment group and 39.4% (13 of 33) in the placebo group (P < or = 0.001). In general, the treatment was well tolerated and was never interrupted because of adverse effects. The number of adverse effects reported in the placebo group was lower than in the treatment group (16 events versus 30 events). All adverse effects reported by patients disappeared within 1 week of completing the treatment. Our findings show that the combination of paromomycin with methylbenzethonium chloride for 20 days is a good alternative for antimonial treatments of cutaneous leishmaniasis in Guatemala.     

Effect of gentiana violet against methicillin-resistant Staphylococcus aureus (MRSA)]

The bactericidal effect of gentiana violet against MRSA isolated from clinical specimens was studied both in vitro and in vivo. The results obtained are as follows: 1) Minimum bactericidal concentration (MBC) of gentiana violet to MRSA was between 0.0025% and 0.08% and the MBC was not influenced even if 25% human whole serum exists in the medium. 2) The number of cells were 2.1 x 10(7) CFU/ml in medium which decreased to 5.4 x 10(4) CFU/ml within 5 min by existing 0.1% gentiana violet in the medium as the final concentration, and also decreased under 10(3) CFU/ml 15 min later. 3) Minimum inhibitory concentration (MIC) of gentiana violet to MRSA was between 0.00015% and 0.00063%, and the inhibitory activity was not influenced even if gentiana violet was incubated with the bacteria in the medium for 72 hr at 37 degrees C. 4) By using an ointment containing 0.1% gentiana violet to 12 cases of patients with the MRSA infected skin lesions, MRSA was eliminated completely from the infected areas of the skin within 4 weeks. 5) The side effects of gentiana violet were not observed in all cases during the use of the ointment containing gentiana violet. It is suggested that gentiana violet may be one of the useful drugs for the treatment of the skin lesions infected with MRSA.     

Aggressive treatment of acute anal fissure with 0.5% nifedipine ointment prevents its evolution to chronicity

INTRODUCTION Anal fissure is a painful condition that affects a sizable majority of the population. The cause is controversial. However, current theories suggest that an initial traumatic tear fails to heal, because of the internal anal sphincter spasm, g…     

Malaria infection induces virus expression in human immunodeficiency virus transgenic mice by CD4 T cell-dependent immune activation

To test the capacity of malaria parasites to trigger virus expression in vivo, human immunodeficiency virus (HIV) transgenic mice were infected with Plasmodium chabaudi chabaudi clone AS. Splenocytes recovered during peak parasitemia showed a dramatic elevation in viral p24 production that returned to baseline by day 15 and failed to rebound at recrudescence or after reinfection. The major sources of virus expression were antigen-presenting cells (APCs) rather than T lymphocytes. Nevertheless, T cells from infected mice stimulated with plasmodial antigen triggered 5-10-fold increases in p24 production from dendritic cells in vitro, which suggests that viral induction stems from interaction of malaria-specific T lymphocytes with HIV-expressing APCs. Indeed, depletion of CD4 T cells resulted in a 70% reduction in the p24 response stimulated by malaria in vivo. These findings demonstrate the ability of Plasmodium species to immunologically activate latently integrated HIV in vivo but suggest that this process may be restricted to acute infection.     

Post lung-stage schistosomula of Schistosoma mansoni exhibit transient susceptibility to macrophage-mediated cytotoxicity in vitro that may relate to late phase killing in vivo

Studies of protective immunity against Schistosoma mansoni in immunized mice suggest that a proportion of challenge parasites may be eliminated after they have passed through the lungs of the host several days after infection; however, no potential immune effector mechanism of resistance against this stage of the parasite has yet been identified, since schistosomes have been shown to rapidly become resistant to antibody-dependent killing mechanisms. In this study, different development stages of S. mansoni were examined for their susceptibility to in vitro cytotoxicity by lymphokine-activated macrophages. As previously shown, newly transformed larvae were readily killed by lymphokine-treated peritoneal macrophages or the macrophage cell line IC-21 (80% mortality over 48 h in vitro), whereas 7 and 10 day old lung-stage parasites had become refractory to macrophage effects. However, after 2 to 2 1/2 weeks of development in vivo, juvenile parasites recovered from the liver were again susceptible to activated macrophage-mediated cytotoxicity (25-65% mortality). Ultrastructural studies of 2 1/2 week old parasites co-cultured with activated IC-21 cells revealed that damage was largely restricted to the areas beneath the parasite surface and gut syncitia; surface membrane disruption was not evident. This late stage of susceptibility was transient and by 4 to 6 weeks liver-stage worms had again become refractory to macrophage killing. The interaction of post lung-stage parasites with activated macrophages was antibody independent. Furthermore, schistosomes isolated from the portal circulation 2 1/2 weeks after infection showed no evidence of surface-bound immunoglobulin in a quantitative immunofluorescence assay, nor did antisera from chronically infected mice (CIS) or mice vaccinated with irradiated cercariae (VS) react with the surface of these parasites in vitro, making the possibility of direct antibody-dependent killing mechanisms unlikely. However, both CIS and VS did recognize excretory/secretory proteins synthesized by 2 1/2 week old liver-stage schistosomes, including a major antigen of approximate Mr (X 10(-3] 220 (220K). It is therefore possible that such antigens might participate in protective immunity, for example via immune complex formation or activation of sensitized T cells. These observations support the role of macrophages as immune effector cells in mice immunized against Schistosoma mansoni, and provide the first physiologically relevant mechanism whereby the immune system might recognize and kill post-lung stage schistosomes.     

Relation of percutaneous coronary intervention of complex lesions to clinical outcomes (from the NHLBI Dynamic Registry)

Advances in percutaneous coronary intervention (PCI) have reduced complications but expanded indications. We used the National Heart, Lung, and Blood Insitute Dynamic Registry to determine clinical outcomes up to 1 year after PCI in 2,839 patients with at least 1 treated complex lesion (defined as a lesion showing evidence of thrombus, calcification, bifurcation or ostial location, or chronic occlusion) and 1,790 patients with only simple lesions treated. Complex lesion interventions were associated (p <0.05) with more sustained major dissections, distal embolization, side branch occlusion, and persistent flow reduction. Patients with treated complex lesions had a lower procedural success rate (93.8% vs 97.3%, p <0.001) and increased in-hospital rates (p <0.001) of death (2.0% vs 0.6%), death/myocardial infarction [MI] (5.2% vs 2.4%), or death/MI/coronary artery bypass graft [CABG] surgery (6.5% vs 2.9%). After adjustment for potential confounders, patients treated for multiple complex lesions were more likely to experience the in-hospital combined end points of death/MI (odds ratio 3.22, 95% confidence interval 2.10 to 4.92), or death/MI/CABG (odds ratio 2.55, 95% confidence interval 1.71 to 3.80). At 1 year, patients with treated complex lesions were more likely (p <0.001) to die (6.2% vs 3.7%), suffer death/MI (11.7% vs 7.5%), or death/MI/CABG/repeat PCI (27.2% vs 23.4%). Patients treated for multiple complex lesions were approximately 50% more likely to die or to have major adverse events than with patients only treated for simple lesions. An increased in-hospital adverse clinical event rate was independently noted for thrombotic, bifurcation, and calcified lesions, and bifurcation lesions had worse long-term event rates.     

十二烷基苯磺酸钠治疗蠕形螨病的实验和临床研究

目的观察十二烷基苯磺酸钠(SDBS)体外杀螨效果、治疗蠕形螨病的疗效及其安全性。方法①观察1%及2%SDBS体外杀螨效果。②临床观察2%SDBS软膏和2%甲硝唑软膏对蠕形螨病的疗效。确诊面部蠕形螨病患者62例,随机分为试验组和对照组(各31例),每天早、晚各1次将药物涂于患处,连续用药8周。用药前、后计数面部炎性损害、蠕形螨感染度及红斑评分,以评价疗效。③治疗8周后随访两个月,观察疗效及副作用。结果①体外杀螨试验,用药5 h,2%SDBS组的螨全部死亡,与2%甲硝唑组(69.4%)及花生油组(9.1%)比较,其差异均有显著性(P<0.05)。2%SDBS杀灭毛囊与皮脂蠕形螨效果,两者间差异无显著性(P>0.05)。②临床试验结果表明,炎性损害、蠕形螨感染度及红斑评分,2%SDBS组治疗前、后差异具有显著性(P<0.05)。治疗后,2%SDBS组(87.1%)与2%甲硝唑组(65.5%)有效率,差异具有显著性(P<0.05)。随访结果无变化。③副作用:2%SDBS治疗皮脂蠕形螨病,3例局部有轻微烧灼感。结论SDBS具有体外杀螨作用,治疗蠕形螨病安全有效。     

Treatment of intestinal amebiasis with paromomycin

Summary Results are presented on the effect of paromomycin on chronic intestinal amebiasis in 35 patients. Thirty-four (97.1%) were free of parasites after a single 12-day treatment; 14 were followed for 3 months, and 20 for 6 months. The importance of very careful, prolonged observation, with examination of stool specimens is emphasized.The authors wish to thank the Parke, Davis Laboratories, Buenos Aires, for the Humatin used in this study.     

Protection against cutaneous leishmaniasis in outbred vervet monkeys using a recombinant histone H1 antigen

Infection with Leishmania major parasites results in the development of cutaneous ulcerative lesions on the skin. We investigated the protective potential of a single, recombinant histone H1 antigen against cutaneous leishmaniasis in an outbred population of vervet monkeys, using Montanide adjuvant. Protection was assessed by challenging the animals with a mixture of vector sand fly salivary-gland lysate and a low dose of in vitro-derived parasites, thus more closely mimicking natural infection induced by L. major. The course of infection in immunized monkeys was compared with that of animals that had healed from a primary infection and were immune. The monkeys immunized with recombinant histone H1 showed a reduced development of lesion size, compared with controls. Our study therefore illustrates the potential use of histone H1 as a vaccine candidate against cutaneous leishmaniasis in humans.     

Chloroquine efficacy in Plasmodium berghei NK65-infected ICR mice, with reference to the influence of initial parasite load and starting day of drug administration on the outcome of treatment

We examined whether the initial number of parasites inoculated and the starting day of medication post-infection influenced the antimalarial efficacy of chloroquine (CQ) against Plasmodium berghei NK65 infection in ICR mice. Male ICR mice were inoculated intraperitoneally with 1 x 10(5), 1x10(6), 1 x 10(7), 1 x 10(8) P. berghei NK65-parasitized erythrocytes (pRBC). In the treated group, all mice received an oral dose of 20 mg/kg of CQ base for 4 days starting on day 0 after infection. From day 3, Giemsa-stained thin blood smears from tail vein blood were used to assess parasitemia. Mice in the untreated control in each group showed a progressive increase in parasitemia leading to death. Treatment of mice, inoculated with 1 x 10(5), 1 x 10(6) and 1 x 10(7) pRBC, with CQ showed a marked effect. All the mice survived during the experiment. During the observation period, malaria parasites could not be detected on microscopic examination. Conversely, mice inoculated with 1 x 10(8) pRBC showed little response to CQ treatment, and all mice showed a progressive increase in parasitemia and ultimately died. In another experiment, mice infected with 1 x 10(3) and 1x 10(5) pRBC were treated with an oral four-day dosage of 20 mg/kg of CQ base from days 2, 3 or 4 post-infection. Treatment of mice, inoculated with 1 x 10(3) pRBC, with CQ from days 2 and 3 showed a marked effect. All mice survived during the experiment. However, treatment from day 4 showed a limited derease in parasitemia and all the mice ultimately died. On the other hand, treatment from day 2 showed a marked effect against 1 x 10(5) P. berghei NK65-infected mice, but treatment from days 3 or 4 was only slightly effective and all the mice died with an increasing parasitemia. The present results indicate that in in vivo antimalarial drug-assay systems, several factors, sush as initial parasite load and starting time of treatment may influence the drug response in the host.     

Effect of transforming growth factor-beta 1 on proliferation and induction of hemoglobin accumulation in K-562 cells

The effects of transforming growth factor-beta 1 (TGF-beta 1) on proliferation and hemoglobinization in K-562 cells, a human multipotential hematopoietic cell line, were studied. We found that TGF- beta 1 could induce hemoglobin accumulation in K-562 cells. Various clones were selected on the basis of the inducibility of hemoglobinization by TGF-beta 1. One high response clone (no. 1) and one low response clone (no. 8) were studied in detail. Hemoglobin accumulation peaked on day 5 of culture in the presence of TGF-beta 1 (0.5 ng/mL, 20 pmol/L), when 90% of clone 1 cells, 55% of parent line cells, and less than 10% of clone 8 cells contained hemoglobin. There was a concomitant reduction in proliferation of 60% for clone 1, 40% for the parent line, and 30% for the clone 8 on day 5 of culture. Quantitative analysis showed that the hemoglobin contents in clone 1 after 5-day induction by TGF-beta 1 and hemin were 1.0 pg/cell and 2.9 pg/cell, respectively. The hemoglobin induced by TGF-beta 1 showed the same electrophoretic characteristics as the hemoglobin induced by hemin. The expression of epsilon-globin mRNA was minimally detectable in control cells and was induced in both TGF-beta 1 and hemin treated cells. Other cytokines with potential effects on K-562 cell proliferation and differentiation were also studied. Interleukin-1, interleukin-3, interferon alpha, interferon gamma, and inhibin, tested as single agents, showed minimal effects on proliferation. None of these agents could induce hemoglobinization or inhibit the hemoglobinization induced by TGF-beta 1.